Dental calculus is a deposit which forms on the surfaces of the teeth at the gingival margin. Supra gingival calculus appears principally in the areas near the orifices of the salivary ducts; e.g., on the lingual surfaces of the lower anterior teeth and on the buccal surfaces of the upper first and second molars, and on the distal surfaces of the posterior molars.
Mature calculus consists of an inorganic material which is largely calcium phosphate arranged in a hydroxyapatite crystal lattice structure similar to bone, enamel and dentine. An organic portion is also present and consists of desquamated epithelial cells, leukocytes, salivary sediment, food debris and various types of micro-organisms.
As the mature calculus develops, it becomes visibly white or yellowish in color unless stained or discolored by some extraneous agent. In addition to being unsightly and undesirable from an aesthetic standpoint, the mature calculus deposits may be sources of irritation of the gingiva.
A wide variety of chemical and biological agents have been suggested in the art to retard calculus formation or to remove calculus after it is formed. Mechanical removal of this material periodically by the dentist is, of course, routine dental office procedure.
The chemical approach to calculus inhibition generally involves crystal growth inhibition and/or chelation of calcium ion which prevents the calculus from forming and/or breaks down mature calculus by removing calcium.
Diphosphonates have been disclosed for use as anti calculus agents. U.S. Pat. Nos. 3,678,154, Jul. 18, 1972; 3,737,533, Jun. 5, 1973; and 3,941,772, Mar. 2, 1976 disclose such compounds.
Dental plaque comprises an accumulation of bacteria and bacterial byproducts on teeth. Plaque adheres tenaciously at points of irregularity or discontinuity such as on rough calculus surfaces, at the gum line and the like. A variety of approaches have been used to combat plaque including stabilized stannous fluoride as disclosed in U.S. Pat. No. 5,004,597 to Majeti et al.
The present inventors have now surprisingly found that stabilized stannous fluoride can be combined with a polyphosphonate to provide gum health benefits as well as less calculus and less stain.
It is an object of the present invention therefore to provide compositions which provide anti plaque and anti calculus benefits.
It is a further object of the present invention to provide products which provide anti plaque and anti calculus benefits with reduced stain.
It is still a further object of the present invention to provide products containing stabilized stannous fluoride and a polyphosphonate.
It is still a further object of the present invention to provide a preferred method of reducing plaque and calculus.
These and other objects will become clearer from the detailed description which follows.
All percentages and ratios used herein are by weight of the total composition unless otherwise specified. Additionally, all measurements are made at 25.degree. C. in the composition or in an aqueous solution/dispersion unless otherwise specified.